Philip Chapman Lesh (March 15, 1940 – October 25, 2024) was an American musician and a founding member of the Grateful Dead, with whom he developed a unique style of playing improvised six-string bass guitar.

[5] He studied the instrument under Bob Hansen, conductor of the symphonic Golden Gate Park Band and became interested in avant-garde classical music and free jazz.

[8] After transferring with sophomore standing to the University of California, Berkeley in 1961, he befriended future Grateful Dead keyboardist Tom Constanten.

[9] At Constanten's suggestion, he studied under the Italian modernist Luciano Berio in a graduate-level course at Mills College in the spring of 1962, where their classmates included Steve Reich and Stanford University cross-registrant John Chowning.

[citation needed] The group changed its name to the Grateful Dead and began playing at Ken Kesey's Acid Tests parties (LSD then being legal in California).

[14] In late 1966 Lesh moved with the group to San Francisco, where they were signed to a recording deal with Warner Brothers, and found himself playing at venues such as the Filmore and the Avalon.

[15] As Lesh had never before played bass he learned "on the job", which meant he had no preconceived ideas about the instrument's traditional role in the rhythm section and was free to develop his own style.

[16] In his autobiography, he credited Jack Casady (the bassist in San Francisco band Jefferson Airplane) as an influence on the direction in which his instincts were taking him.

[19] Contemporary bass players such as Casady, Bruce, James Jamerson, and Paul McCartney had adopted a more melodic, contrapuntal approach to the instrument.

Joe Smith of Warner Bros. wrote a letter about cost overruns that had accumulated during studio sessions for the band's second album, Anthem of the Sun (1968).

According to music critic Stephen Thomas Erlewine, Smith singled him out as "the catalyst for chaos within the band", writing: "It's apparent that nobody in your organization has enough influence over Phil Lesh to evoke anything resembling normal behavior.

"[22] Lesh was not a prolific composer or singer with the Grateful Dead, though he did occasionally make contributions such as the opening track on American Beauty, "Box of Rain".

[23] His high tenor voice contributed to the Grateful Dead's three-part harmony sections in their group vocals in the early days of the band, until he largely relinquished singing high parts to Donna Godchaux (and subsequently Brent Mydland and Vince Welnick) in 1974 because of vocal cord damage from improper singing technique.

All of the band's shows were recorded by Deadhead tapers, and it became possible to listen to any given performance from 1972 or 1974 and hear the Grateful Dead interpreting the musical innovations that Lesh stimulated through Coltrane's influence.

He later introduced the band to composer Charles Ives, which created their ability to go spontaneously from a discordant jam into a blues or country song.

In the early 2010s he performed select shows at venues throughout the United States, notably the Capitol Theatre in Port Chester, New York, as well as at festivals.

[48] On October 26, 2006, Lesh stated on his official website that he had been diagnosed with prostate cancer, the disease that killed his father, and would be undergoing an operation in December 2006.